Ring & pinion gear

[66chargertoy]

Ok, I'll get right to the point! Was getting a loud whining sound while cruising (thought it was coming from the passenger seat, but the wife set me straight ) coming from the rear end. Bought the unit last year from someone that had it on the shelf. Pulled the unit and brought to a local transmission and differential guru in my area. Its a 741 with a 323 sure grip. Sure enough, ring and pinion are just worn pass its freshness date. Looking on line for a new set, so question is, does it have to be a ring & gear specifically for a 741, or can the ring & pinion come from a 742 or 489.
Thanks.
Denis

[jlatessa]

Ring and pinion sets are carrier specific....all three pinions have a different shaft design.
I reality, the ring gear is the same, I've heard, but you'll need a set of new gears anyway.

Funny I ran across your post today, I am just cleaning up another housing for our 70 Charger.
When I installed the axle shafts on the driver side of the old housing I had some up and down movement of the bearing.

After test fitting the old axle to the newer housing, all is good.
I had to drill and tap another hole for the breather as this housing had it located more inboard, older I think,
and the brake line junction would not be right.

Joe

[66chargertoy]

Ah!!!!!!!!!!!! Crap That's what I thought. Plenty of 742 & 489s on line. Thanks jlatessa. The shop is looking for a set also, just thought I could find something sooner. Anyone have a ring & pinion lying around gathering dust that needs a new home
Denis

[firefighter3931]

Denis, the aftermarket doesn't seem to support anything in the 3.23 range. All i've seen is 3.55 and up. 

Unless you can find a nice set of originals for the 741 case ?


Ron

[Dino]

Ack!  A 741 case 3.23 sure grip just got sold on my local CL!

They're getting hard to find but they're out there.  Plenty opens to be found but sure grip 3.23's are scarce.

You'll likely have more luck finding the complete pumpkin in which case it doesn't matter what case it's in.

[John_Kunkel]

Denis, the aftermarket doesn't seem to support anything in the 3.23 range.

Nitro Gears has 3.23's for the 489.

http://www.nitro-gear.com/ring-pinions/

[66chargertoy]

It would seem that I can get 3.55 gears for the 741 case easily, so I would like to throw this out to all of current mopar owners out there, how do you like this gear? Tires are 275/60/15, 727 trans with a 2500 stall converter from Hughes. Is highway cruising with 3.55s a problem? Just like to get the charger back on the road, looks sad sitting in the driveway with its but up in the air

[66chargertoy]

Well it's back on the road Went ahead and got the 3.55 from Summit, also the bearing kit so the whole unit will be fresh and ready to go. Also changed out the speedometer pinion gear so I know exactly how fast I'm not supposed to be going Was a little apprehensive about the gears, but for the amount of highway I do, it's a pretty good balance. The local trany guru that Ron recommended set up the unit for me. Very happy

[firefighter3931]

Cool 

So the rear end noise is fixed....now you have to fix the whine from the passenger seat ! 

Some duct tape should fix that problem !! 

Like we discussed ; the 3.55's with a 28in tire is the same as the 3.23's with the old 26in you had on there before so really, nothing has changed. 


Ron